(1) Field of the Invention
The present invention relates to a face plate adapter for securing tubular stock in a lathe or other machine tool, so that the inner surface of said stock may be finished or machined.
(2) Description of the Prior Art
Many automatic or manual machine tool procedures are of the type in which the feed or stock material is a tubular metal bar. In machining tubular stock, and particularly the inner surface thereof, it is necessary to secure the tubular stock at both ends in the machining tool. In a typical machining tool such as a lathe, tubular stock is secured at one end by a chuck or other conventional adjustable securing means, and by a tail stock or a machine steady rest, on the opposing end. When the tubular stock is grasped by these standard securing means, considerable clamping pressure is transferred to the tubular stock and distortion of the roundness thereof can occur. The distortion in the roundness of the tubular stock caused by the clamping pressure typically causes out-of-roundness to result on the finished surface after machining thereof. The degree of the distortion caused by the clamping pressure is directly related to the wall thickness of the tube. The thinner the wall thickness of the tube the greater the potential for distortion of the roundness of the tubular stock.
Although there have heretofore been known various devices for holding or steadying feed material or stock in machine tools, none of the prior art references addresses the problem of distortion of tubular stock caused by the grasping of tubular stock by the conventional clamping means heretofore used.